Breech bolt locking means comprising a resilient split ring having locking lugs thereon



Nov. 1'7., 1970 D. s. CREAM ETAL 3,540,147

BREECH BOLT LOCKING MEANS COMPRISING A RESILIENT SPLIT RING HAVING LOCKING LUGS THEREON Filed July 25, 1968 M m rf. m. 5 W wJ afin/wa ATTORNEYS United States Patent O U.S. Cl. 42-16 5 Claims ABSTRACT OlF THE DISCLOSURE A breech block lock, including a plurality of locking lugs which are carried on the breech block and adapted to be simultaneously operated by a ring pin supporting assembly movably positioned within the breech block.

BACKGROUND OF THE INVENTION It is well known in the case of breech loading firearms to employ a construction in which barrel and breech block are locked together during ring by a breech block carried locking block which is adapted to be received within a recess provided in an extension of the barrel. Normally, a breech block slide suitably guided for reciprocation within the receiver of the gun is employed to carry the breech block and actuate the locking block. The slide may be operated by various conventional actuators, such as a manually operated straight pull handle mounted thereon, action bars which extend to a manually operated slideable forearm, or action bars operated by various gas piston and spring assemblies.

One disadvantage of prior breech block locking arrangements of this type is that during tiring, force is not equally distributed to the barrel extension, which tends ot result in slight tilting movement of the breech block with resultant loss of gas and/ or the unequal distribution of gas pressure across the firing chamber.

SUMMARY OF THE INVENTION The present invention is directed towards an improvement in breech block locking arrangement of the type described above, wherein a locking block is provided with a plurality of locking lugs adapted to eifect equal distribution of forces to the barrel extension. Specifically, the locking lugs are mounted on a flexible metallic split ring, which is adapted to be expanded into breech block lock ing position by contact with a tiring pin supporting assembly slideably positioned within the breech block.

DRAWINGS The nature and mode of operation of the breech block lock of the present invention will be more fully understood by reference to the following description taken with the accompanying drawings, wherein:

FIG. 1 is an externally side elevational view of the receiver portion of an automatic shotgun;

FIG. 2 is a fragmentary view similar to FIG. l, but showing different parts thereof broken away to show a breech block in breech closing position prior to locking thereof;

FIG. 3 is a fragmentary view similar to FIG. 2, but showing the breech block in its rearmost position;

FIG. 4 is a sectional view taken generally along the line 4--4 in FIG. 2, but showing the locking lugs of the split ring locking block moved into locking position; and

FIG. 5 is an enlarged view of the split ring locking block shown in FIG. 4.

3,540,147 Patented Nov. 17, 1970 ICC DETAILED DESCRIPTION While not limited thereto, the present invention will now be described for purposes of illustration with particular reference to its use in a conventional automatic shotgun, designated as 1 in FIGS. l and 2.

Referring particularly to FIGS. 1 and 2, it will be seen that shotgun 1 generally includes a receiver portion 2 having affixed to one end thereof a stock 3, and having afxed to the other end thereof a barrel 4 having cartridge receiving or tiring chamber 5 and a tubular magazine 6. Magazine 6 is adapted to slideably receive four or more cartridges, designated as 7, which are normally biased rearwardly towards receiver 2, by spring means, not shown.

Receiver 2 is shown as being elongated lengthwise of gunshot 1 and as having spaced side walls 8 and 9, a top wall 10 and as being open at the bottom. The rearwardly extending portion of the open bottom of receiver 2 is closed by a conventional trigger assembly 11 including trigger 12 and hammer 13. The forwardly extending portion of the open bottom of receiver 2 defines an opening 14 through which cartridges 7 may be loaded into magazine tube `6. Immediately adjacent trigger assembly 11 and above opening 14 is disposed a conventional, pivotally supported cartridge lifter assembly 15, which is adapted to elevate cartridges forced rearwardly from magazine 6 into feed position, as indicated in phantom in FI-G, 3, whenever gun 1 is cocked in the manner to be described.

Disposed Within receiver 2 is a breech block 16, which is slideably carried on a breech block slide 17, which is in turn suitably affixed, as by a key not shown, to the rearwardly extending end of a forked arm action bar assembly 18 for movement therewith. Action bar assembly 18, which may be of conventional design, is supported by suitable guides, not shown, carried on receiver side walls 8 and 9 for reciprocation lengthwise of receiver 2, so as to move breech block 16 between a forward breech block closing position, indicated in FIG. 2, and a rearward cocked position, indicated in FIGS. 1 and 3.

Action bar assembly 18 may be normally maintained in its forward position by means of closing or return spring 19, which is received within stock 3 and connected to the action bar assembly by rod 201. It will be understood that upon ring of gun 1, action bar assembly 18 is adapted to be reciprocated rearwardly by the recoil force of the explosion via a gas operated piston, not shown, in order to compress closing or return spring 19, set hammer 13 in the cocked position and finally actuate lift assembly 15 to elevate a new cartridge into the feed position. Thereafter, spring 19 is normally permitted to return action bar assembly 18 to breech closing position, during which movement lift assembly 15 is depressed and a cartridge previously positioned thereby is fed by breech block 16 into receiving chamber 5. Preferably, suitable means, not shown, are provided to releaseably retain action bar assembly 18 in its rearward position, when magazine 6 has been emptied of cartridges.

Further, as is conventional breech block 16 is provided with a suitable extractor 21, which is adapted upon rearward movement of the breech block to withdraw a spent cartridge from the cartridge chamber 5. Upon movement of breech block 16 into its cocked position a suitable` ejector pin 22, carried upon receiver side wall -8 is adapted to engage the rim of the withdrawn cartridge to effect ejection thereof through ejection opening 23 provided in receiver side wall 9. Provided in communication with ejection opening 23 is an elongated slot 24, which is adapted to receive breech block slide mounted pull handle or cocking lever 25, during movement of breech block 16 and slide 17 to their rearmost positions. Pull'handle 25 may be removably affixed to slide 17 by any suitable means, such as a spring biased ball detent shown only in FIG. 2.

Now referring particularly to FIGS. -2 and 4, it will be seen that in accordance with the present invention, breech block 16 is formed by a tubular side wall portion 26, having integrally fonmed front and rear end walls 27 and 28, which are provided with axially aligned through bore openings 29 and 30, respectively. Tubular side wall 2-6 is provided adjacent the rearwardly extending end thereof with a lengthwise extending through slot opening 31, terminating in forward and rear abutment surfaces 32, 33, respectively, which are adapted to cooperate with breech block slide 17 in the manner to be described. Any suitable means, not shown, may be provided to releaseably maintain slide 17 in position within slot 31 for slideable movement lengthwise thereof between abutment surfaces 32, 33. It will be understood that tubular side wall 26 is also provided with a lengthwise extending slot, not shown, which is adapted to freely receive pull handle 25.

-In FIG. 4, the forwardly extending end of tubular side wall 26 is shown as being provided with a pair of aligned radially extending bore openings 34, 3:4', which are adapted to be disposed in alignment with locking shoulder defining recesses 35, respectively, provided in extension 36 of barrel 4, when breech block 16 is moved into its breech closing position.

A novelly constructed locking block 40 of the present invention is shown particularly in FIGS. 4 and 5 as being in the form of a flexible or resilient, metallic split ring provided on the radially inwardly and outwardly facing surfaces thereof with pairs of aligned cam follower pins 41, 41' and locking lugs 42, 42', respectively.

As will be apparent from viewing FIG. 4, locking block 40` may be removably supported within breech block 16 by locking lugs 42, 42', which are adapted to be freely received within breech block side wall openings 34, 34', respectively. Preferably, when locking block `40` is unexpanded or in its normal inoperable position, the outwardly facing free ends of locking lugs 42, 42' are disposed flush with the outwardly facing surface of breech block side wall portion 26 or slightly recessed within openings 34, 34. It will be understood that when breech block 16 is moved into breech closing position, so as to align openings 34, 3-4' with recesses 35, 35', locking block 40 may be expanded or moved into its operative position in order to extend or force the outwardly facing ends of locking lugs 42, 42' to move outwardly into breech block locking engagement within recesses 35, 35.

Further, in accordance with the present invention a firing pin supporting assembly is, as shown in FIG. 2, slideably supported lwithin breech block rear wall bore opening 30 for reciprocation axially thereof. Assembly 50 includes a `generally cylindrical member 51 provided on the forwardly extending end thereof with a frusto-conically shaped cam surface 52 positioned concentrically of an axially extending, stepped bore opening 53, which is adapted to slideably receive a lfiring pin 54 for reciprocation axially thereof. Member 51 is also provided with a downwardly opening recess 55, which is adapted to receive slide 17. It will be understood that member 51 is provided with a transversely extending opening, not shown, 'which is disposed in communication with the upper or closed end portion of recess 55 and adapted to receive handle 25. When the inner end of handle 2.5 is positioned adjacent the upper or closed end of recess 55 and aflixed to slide 17 by ball detent 25', member 51 is effectively located for reciprocating movement with slide 17 in the manner to be hereinafter described.

The degree of movement of firing pin 54 within stepped bore opening 53 may be limited by member carried motion limiting pin 58, which is adapted to be slideably received within elongated slot opening 59 provided in the enlarged rearwardly extending end portion 60 of the firing pin. Firing pin 54 is normally biased to its rearmost position with respect to member 51, shown n FIG. 2, by means of a compression spring 61.

By referring to lFiIG. 2, it will be seen that breech block slide 17 is modified in accordance with the present invention by providing an upstanding flange portion 65, which is adapted to project upwardly through breech block slot 31 and be received within downwardly opening slot recess 55 of member 51. The rearwardly facing surface i66 of flange portion 65 defines an abutment surface adapted to cooperate with rear abutment surface 313 of breech block .16. The forwardly facing surface 67 of flange portion 65 is provided with a bore opening 68 adapted to slideably receive a plunger 69 and compression spring 70.

It will be understood that when action bar assembly 18 is moved towards its forward position, plunger 69 is forced into engagement with breech block abutment surface 32 in order to force the breech block towards the right, as viewed in FIG. 2, into its breech closing position. The spring constant of spring 70 is chosen such that plunger 69 will not be significantly depressed or forced inwardly of bore opening 68 until movement of the breech block is positively arrested due to positioning of a cartridge within chamber 5 and closing of the breech. Thereafter, spring 70 functions to resiliently maintain breech block 16 in breech closing position, while permitting slide flange portion and thus member 51 carried thereon to reciprocate forwardly of the breech block towards front wall 27. Upon relative fonward reciprocation of member 51, frusto-conical cam surface 52 is forced into operable engagement with cam follower pins 41, 41' in order to effect expansion of locked block 46 into its operative position, wherein locked lugs 42, 42' are extended and disposed in breech block locked engagement within locking shoulder defining recesses 35, 35'. 4It will be noted that when member 51 is reciprocated into its forward locking block operating position, it additionally functions to place lfiring pin actuating end portion 54 in position immediately adjacent to rear surfaces of a cartridge received within chamber 5. While, the extent of forward travel of member 51 may be controlled by any suitable means, it is preferable that its forward travel be limited by abutting engagement with breech block front wall 27.

Thereafter, when trigger 12 is pulled, hammer 13 will be propelled against firing pin enlarged end portion 60, so as to propel the actuating end 54' of firing pin 54 through front wall opening 29 into engagement with cartridge 7. Thereafter, the recoil from the explosion will force the action bar assembly 18 towards its rearmost position in the manner previously described.

During rearward movement of action bar assembly 18, slide flange 65 will be forced rearwardly within slot 31 of breech block 16 to initially effect rearward reciprocation of member `51 relative to breech block 16 in order to remove cam surface 52 from operative engagement with locking block cam follower pins 41, 41', whereupon the locking block 40 is permitted to return to its normal inoperative position and free the breech block for subsequent movement. Upon continued rearward movement of slide flange 65, its rear abutment surface 66 is moved into engagement with breech block rear abutment surface 33, so as to initiate rearward movement of the breech block towards its rearmost position. During rearward movement of breech block 16, hammer 13 is engaged thereby and moved into its cocked position, so as to permit compression spring 61 to return firing pin 54 to its original rearwardly disposed position.

While there has been described only a preferred embodiment of the present invention, it will be understood that various additions to and modifications thereof will become apparent to one skilled in the art in view of the foregoing description. Exemplary thereof would Ibe to omit the cam follower pins provided in the locking block, in which case the cam operating surface would directly engage the radially inwardly facing surface of the locking block slide ring. Additionally, the locking block may be modified by increasing the number of locking lugs employed. Further, only one annularly extending locking shoulder defining recess may be provided for receipt of the several locking lugs, and the locking shoulder defining recess or recesses may be formed in the side walls of the receiver, rather than the barrel extension. Still further, while the breech block lock of the present invention has been specifically described with reference to its use in an automatic shotgun, it will be readily apparent that it has utility both in manually operated Shotguns and other firing arms. Accordingly, the scope of the present invention is to be limited only `by the scope of the appending claims.

We claim:

i. In a firearm having a receiver, a breech block disposed within said receiver for reciprocation to and from a breech closing position, and locking shoulder defining means, the improvement which comprises: locking block means moveably supported `by said breech block for movement from a normally retracted position to an extended position, said locking block means being in the form of a resilient split ring adapted when said breech block is in said breech closing position to be extended into locking engagement with said locking shoulder means at least at two points, spaced peripherally of said breech block; and a firing pin supporting assembly receivable within said breech `block for reciprocation with respect thereto in alignment with said path of reciprocation, said assembly when reciprocated `while said breech block is in said breech closing position being adapted to slida'bly engage said split ring to move said split ring into said extended position.

2. The improvement in a firearm according to claim 1, wherein said breech block is provided with openings exteding transversely of the path of reciprocation thereof, said split ring includes locking lugs received within said openings and adapted to be projected outwardly therethrough from a normally retracted position and said assembly is adapted to expand said split ring to force said locking lugs from said retracted position outwardly through said openings into locking engagement with said locking shoulder means.

3. The improvement in a firearm according to claim 2, wherein said assembly includes a member having a through opening disposed parallel to the path of reciprocation of said assembly and a firing pin slideably received within said through opening and having a cartridge firing end portion adapted to project through an outlet end of said through opening, said member terminating adjacent said outlet in a cam surface of revolution whose axis is aligned with said path of reciprocation, said cam surface being adapted to be placed in operable engagement with said split ring to effect expansion thereof.

4. The improvement in a firearm according to claim 3, wherein cam follower pins are mounted on said split ring in alignment with said locking lugs, and said cam surface is adapted to be placed in surface engagement with said cam follower pins to effect expansion of said split ring.

5. The improvement in a firearm according to claim 1, wherein said breech block inclu-des a side wall portion interconnecting a rear wall and breech closing front wall, said rear and front walls having through openings aligned with said path of reciprocation, said side wall portion being provided adjacent said front wall with openings extending transversely of said path of reciprocation; said split ring includes locking lugs received within said transverse openings and adapted to be extended outwardly therethrough from a normally retracted position into locking engagement with said locking shoulder means when said locking lugs are positioned in alignment therewith, said split ring serving to normally maintain said locking lugs in said retracted position; said assembly includes a member, said member being slideably supported adjacent a rear end portion thereof within said rear wall opening for reciprocation in alignment with said path of reciprocation and having a front end portion thereof provided with cam surface means adapted to be placed in operable engagement with said split ring to effect expansion thereof, said member having a through open ing extending through said front end portion in alignment with said path of reciprocation, and a firing pin slideably supported within said member opening, said firing pin having a cartridge firing end portion disposed adjacent said member front end portion and adapted to be projected through said front wall opening upon operation of said firing pin; and means are provided to effect reciprocation of said breech block to and from breech closing position, said reciprocating means upon movement thereof in a first direction being adapted in sequence to move said breech 'block into said breech closing position wherein said locking lugs are positioned in alignment with said locking shoulder means, and thereafter move said member with respect to said ybreech block in order to position said cam surface means in operable engagement with said split ring.

References Cited UNITED STATES PATENTS 2,775,166 12/1956 Janson 42-16 2,900,877 8/1959 McClenahan 42-l 6 3,283,435 11/1966 Koch 42--16 3,370,372 2/1968 Thompson 42-16 BENJAMIN A. BORCHELT, Primary Examiner C. T. JORDAN, Assistant Examiner 

